Safety and Performance of the Steroid-Releasing S8 Sinus Implant: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety and Performance of the Steroid-Releasing S8 Sinus Implant (NCT01894503), a na phase 2 study. The primary outcome is Number of Sinuses With Successful Implant Delivery.

2. Clinical Question

The study was intended to assess safety and performance in patients with recurrent sinus obstruction after sinus surgery. A separate listed outcome concerned the number of patients with plasma mometasone furoate concentration above the lower limit of quantification. Its result is not reported in the registry record. The available record therefore describes the clinical question and outcomes but does not provide outcome estimates that would answer whether delivery succeeded or what plasma concentrations were observed.

3. Trial Design

This was a phase 2, completed, single-group study sponsored by Intersect ENT. The registry lists enrollment of 5 and gives the study start as 2013-06 and primary completion as 2013-10. Allocation is recorded as NA, and masking as none. Those entries are consistent with a study in which all enrolled participants received the intervention, rather than a randomized comparison between groups.

The intervention was bilateral in-office placement of the S8 Sinus Implant in the ethmoid sinuses. The device contained mometasone furoate, 1350 mcg. The registry describes the purpose as assessing safety and performance in post-sinus surgery patients presenting with recurrent sinus obstruction. It does not describe a comparator treatment, placebo, or untreated control group.

The primary endpoint was assessed at the end of the baseline procedure and was defined as the number of sinuses with successful implant delivery. Its stated population included all sinuses in which placement was attempted. This is a sinus-level endpoint, whereas enrollment is reported at the participant level; the number of attempted sinuses is not reported in the registry record. The listed secondary outcome concerned patients with plasma mometasone furoate concentration above the lower limit of quantification.

The record lists two outcome measures and zero analyses. It does not report the observed primary or secondary outcome results, an analysis method, or an analysis population for the secondary outcome. The design can therefore be described, but the registry information does not support an estimate of delivery success or a comparative assessment of safety or performance.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: A total of six patients were enrolled (consented). One patient did not have the required grade 2 polyposis on at least one ethmoid side and was excluded. The remaining five patients meet all eligibility criteria and underwent an in-office bilateral placement of two S8 Sinus Implants. All five patients completed follow-up through the Day 90 visit.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Per-treatment evaluable population, consisting of all sinuses in which placement of the S8 Sinus Implant was attempted.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Number of Sinuses With Successful Implant Delivery, measured over End of baseline procedure.

The primary endpoint counts sinuses with successful implant delivery at the end of the baseline procedure. Success is defined procedurally: access to the target ethmoid sinus and deployment of the S8 Sinus Implant. This endpoint measures whether placement was accomplished, not whether symptoms changed, whether obstruction improved, or how long any result lasted.

A delivery endpoint is useful for describing procedural performance. It can distinguish attempted placements from placements that meet the stated technical definition, provided the number of attempts and the number meeting the definition are reported. Here, the registry specifies that the evaluable population consists of all sinuses in which placement was attempted, but does not report how many sinuses were attempted or how many were successfully treated. The observed endpoint result is therefore not reported in the registry record.

The unit matters when interpreting this outcome. The endpoint is expressed in sinuses, while enrollment is expressed in participants. Bilateral placement is described, but that description does not establish how many sinuses were actually attempted or evaluable. Without the endpoint count and its denominator, delivery success cannot be quantified from this record. Nor does a technical delivery outcome by itself establish clinical benefit or provide a comparison with another approach.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies a count-based primary endpoint: the number of sinuses with successful implant delivery. It also lists a patient-level secondary outcome based on plasma mometasone furoate concentration. These outcomes have different units and answer different questions. The first concerns technical delivery; the second concerns how many patients had a measured concentration above the stated quantification threshold. The record does not report outcome values or statistical analyses for either measure.

What does a count endpoint convey?

A count records how many units meet a specified condition. Here, the units are sinuses, and success is defined as access and deployment of the implant in a target ethmoid sinus at the end of the baseline procedure. A count can be informative, but interpretation depends on knowing the number of units assessed. A count without the number of attempted placements does not establish the proportion of attempts that succeeded. The registry specifies that the endpoint population consists of sinuses in which placement was attempted, but it does not report the number attempted or the number successful.

Count outcomes also differ from continuous measurements, such as a symptom score, and from time-to-event outcomes, such as time until an event occurs. A count does not inherently describe magnitude beyond the number of qualifying units, and it does not supply a comparison unless an appropriate reference group or baseline is available. In this single-group record, no comparator is listed. The endpoint definition therefore supports a description of procedural success, but the missing result prevents even that description from being quantified.

Why distinguish sinuses from participants?

The primary endpoint is at the sinus level, while enrollment and the secondary outcome are described at the participant level. Those units should not be treated as interchangeable. When more than one measurement can come from a participant, measurements from the same person may be related rather than statistically independent. As a general statistical consideration, an analysis of multiple units within people may need to account for that clustering. The registry record does not report whether such an analysis was conducted or what method was used. It also does not give the number of attempted sinuses, so the structure of the endpoint data cannot be reconstructed from the record.

What would uncertainty measures add?

In general, a confidence interval describes a range of values compatible with the data under a specified statistical model. It conveys precision as well as the point estimate: a more uncertain estimate has a wider interval, while a more precise estimate has a narrower one. An interval does not remove concerns about study design, missing data, or bias, and it cannot create a comparator where none exists. No confidence interval or primary endpoint estimate is reported in the registry record, so the precision of delivery performance cannot be evaluated.

For a count outcome, a statistical analysis may need to reflect how counts were generated and whether observations are independent. Over-dispersion is a general concern when count data vary more than a basic model assumes; if present, a model that allows extra variability may be more appropriate than one that assumes a tighter count distribution. This is general statistical context, not a description of the method used in this study. The registry record reports zero analyses and does not specify a count model, assumptions, or adjustments. It is not possible to determine whether over-dispersion was assessed.

How should the planning illustration be read?

Planning sample sizes and analyzing observed outcomes are different tasks. The registry's planning assumptions describe an illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The described trial, however, is single-group and has no randomized comparison. Those hypothetical two-arm assumptions do not describe the enrolled design or establish the study's original design rationale. The sample-size justification is not reported in the registry record.

A planning illustration asks what sample size might be needed under stated assumptions to detect an effect of a specified size. Such a calculation is not observed power and is not evidence that an effect was detected. In general, power is a property of a design under assumed conditions; it does not measure how convincing a completed study's result is. Because the primary endpoint result and its analysis are not reported, the registry information does not support a conclusion about how well the study could detect a delivery effect. Any planning values should be read as conditional illustrations, not as observed findings or proof that the completed study was adequately powered.

The record also does not report a statistical analysis plan, interim analysis procedures, or inferential methods. It is therefore not possible to determine whether analyses were prespecified, whether model assumptions were checked, or how estimates and uncertainty were intended to be calculated. General statistical concepts can clarify what a complete analysis would need to address, but they should not be mistaken for methods documented for this trial.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures: the primary count of sinuses with successful implant delivery and the secondary count of patients with plasma mometasone furoate concentration above the lower limit of quantification. It reports zero analyses. No multiplicity strategy, such as a prespecified approach to interpreting several outcomes, is reported in the registry record. The record also does not state whether either outcome was designated for a formal hypothesis test or whether other outcomes were assessed.

Multiplicity matters in general when several outcomes or comparisons are tested: the chance of a false-positive finding can increase if results are interpreted without accounting for the testing strategy. That general concern does not imply that such testing occurred. Since no analyses or outcome results are reported, the registry entry does not allow assessment of multiplicity in practice.

Missing-data methods are not reported in the registry record. The primary endpoint definition identifies the per-treatment evaluable population as the sinuses in which placement was attempted, but the record does not state whether any attempted placements or outcome observations were missing, how missing observations were handled, or whether all enrolled participants contributed to each outcome. The stated primary endpoint population should not be taken as evidence that data were complete.

The record does not report an analysis population for the secondary outcome or a statistical analysis plan. It also does not describe imputation, exclusions, sensitivity analyses, or adjustments. These omissions limit reproducibility and make it difficult to assess whether the reported enrollment and the populations relevant to each outcome would have matched. Because results are not reported, the effects of missingness or multiplicity on estimates cannot be evaluated.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

For the S8 Sinus Implant group, the registry reports serious adverse events affecting 0 of 5 participants at risk. Other adverse events affected 2 of 5 participants at risk, and deaths were 0. These are counts of affected participants in the registry’s safety summary; they are not a comparison between treatments.

The label for other adverse events is not further defined in the record, and no top serious adverse-event terms are listed. The record does not report event descriptions, timing, severity beyond the serious classification, or whether events were considered related to the implant. The figures therefore cannot identify what happened to the participants or how events were assessed.

These counts are descriptive and should be read in the context of enrollment of 5. A zero count of serious events in this group does not prove that serious events cannot occur, while the count of other events does not establish causation. The registry record does not provide a comparative safety analysis, confidence intervals, or a detailed account of event collection. The figures describe what the record reports, not a complete estimate of safety.

12. What the Result Does, and Does Not, Mean

The study record is useful for identifying a specific procedural question: whether the S8 Sinus Implant could be accessed and deployed in target ethmoid sinuses at the end of the baseline procedure. It also identifies a secondary question about plasma mometasone furoate concentrations and provides a small set of adverse-event counts. Those details clarify what the investigators intended to examine.

However, the primary endpoint result and the secondary outcome result are not reported in the registry record. There is no reported count of successful deliveries, no reported number of attempted sinus placements, and no reported result for patients above the concentration threshold. Without those data, the record does not quantify the implant’s procedural performance or plasma concentration findings.

The single-group design also sets a limit on interpretation. There is no randomized control group, so the registry entry does not estimate a difference against an alternative treatment or control condition. A descriptive outcome in one group, even if reported, would not alone establish what would have happened under another approach. No inferential analysis or estimate of uncertainty is reported, further limiting assessment of precision.

The safety summary reports 0 serious adverse events among 5 at risk, 2 affected by other adverse events among 5 at risk, and 0 deaths. These observations are not a guarantee of safety and do not determine whether events were caused by the intervention. The record does not provide enough detail to characterize the other events.

Accordingly, the registry information supports a description of the study’s design, endpoint definition, and recorded safety counts. It does not support a conclusion about the magnitude or certainty of delivery success, the secondary concentration outcome, or comparative benefit or harm. Those conclusions would require outcome and analysis information that is not reported in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically notable because the primary outcome is defined at the sinus level while enrollment is reported at the participant level. That distinction affects the denominator needed to interpret a count of successful placements. The record defines which sinuses belong in the primary endpoint population, but does not report the number attempted or the count that met the success definition. The result therefore cannot be translated into a rate or otherwise quantified from the registry entry.

The single-group design is another important feature. Without a comparator, the trial is not a like-for-like test of the implant against another intervention. This does not prevent a study from describing procedural outcomes, but it limits what can be said about comparative effects. The absence of masking is also recorded; the registry does not describe methods that would reduce awareness of treatment assignment, and there is no allocation between groups to assess.

The record illustrates why outcome definitions and outcome reporting are separate requirements. A precise definition makes clear what success was intended to mean, but does not tell the reader how often it occurred. Similarly, the adverse-event counts provide a limited description but not detailed event characterization or a comparative safety estimate.

Finally, planning illustrations should be separated from evidence about the completed study. The stated sample-size assumptions describe a hypothetical two-arm calculation, while the registered design is single-group. Such planning calculations are conditional and are not observed power. Taken together, the record highlights how design, unit of analysis, denominators, outcome reporting, and uncertainty all shape what can be inferred from a small clinical evaluation.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The principal limitation for interpretation is that the registry record does not report the primary endpoint result. It defines successful delivery and the eligible sinus-level population, but provides neither the number of successful placements nor the number attempted. The secondary outcome result is also absent. Consequently, the main performance question cannot be answered from the record.

Enrollment was 5, and the study had a single-group design. There is no concurrent comparator, randomized allocation, or masking. As a result, the record cannot support a comparative effect estimate. Even descriptive findings would be limited in precision, and the absence of reported estimates or confidence intervals means that precision cannot be assessed directly.

The difference between the participant-level enrollment and sinus-level primary endpoint is important. The record does not report the number of sinuses attempted, how within-participant observations were handled, or whether any attempted placements were excluded from the evaluable population. These details would be needed to understand the endpoint denominator and the analysis structure.

Safety reporting is limited to counts of affected participants. The record does not describe the other adverse events, their timing or severity, or their assessed relationship to the implant. The listed counts therefore provide only a narrow summary and do not establish causality or comparative risk.

Finally, the registry record reports zero analyses and does not report methods for missing data, multiplicity, or statistical modeling. It does not provide a sample-size justification for the registered single-group design. The planning assumptions describe a two-arm illustration and should not be treated as the trial’s protocol or as evidence of observed power. These omissions constrain reproducibility and the scope of conclusions.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Safety and Performance of the Steroid-Releasing S8 Sinus Implant — NCT01894503.
• Registry record last updated 2018-07-18; status last verified 2017-03.
• Results first posted 2018-06-25.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT01894503 is a completed phase 2, single-group study of the S8 Sinus Implant in post-sinus surgery patients with recurrent sinus polyps and recurrent sinus obstruction. Enrollment was 5. The intervention was bilateral in-office placement of the implant in the ethmoid sinuses; the implant contained mometasone furoate, 1350 mcg.

The primary endpoint was the number of sinuses with successful delivery by the end of the baseline procedure, defined by access and deployment in the target ethmoid sinus. Its result is not reported in the registry record. The listed secondary outcome concerned patients with plasma mometasone furoate concentration above the lower limit of quantification; its result is also not reported. The record lists zero analyses.

The safety summary reports 0 serious adverse events among 5 at risk, 2 affected by other adverse events among 5 at risk, and 0 deaths. No comparator group is listed, and the record does not provide comparative estimates or uncertainty measures.